1. Technical Field of the Invention
The present invention relates generally to an encoder, a decoder, and a record carrier, and more particularly to an encoder compressing data to store it on a record carrier, a decoder expanding data that has undergone data compression and been recorded on a record carrier to reproduce it, and a record carrier storing therein data in data compression.
2. Background of Related Art
Optically readable discs such as "Compact Discs" have come into wider use as audio record carriers than conventional magnetic tapes. An EFM recording format using 8-bit fixed length data symbols and a data format including a subcode, audio data, and a CRC are established as logical formats for CDs. CD players having a variety of application functions are now being developed.
CDs are also used as CD-ROMs by discriminating control bits (four bits) in a subcode of a Q channel or detecting the absence of a TOC (Table of Contents) and have wide applicability to the field of electronic publication for mass storage and high-speed access. The CD-ROMs, however, have the drawback in that audio signals are compressed by ADPCM, which makes it impossible to reproduce the audio signals at original quality levels. A recording system designed to achieve the high fidelity is, thus, sought. In other words, development of optical discs capable of recording audio signals within a band of twice that of a conventional CD is expected.